Synthesis of a resin monomer-soluble polyrotaxane crosslinker containing cleavable end groups

Preparation and Application of Polyrotaxane Cross-Linking Agent Based on Cyclodextrin in Gel Materials Field

The cross-linking point of a conventional chemical cross-linking agent is fixed. Therefore, gels that are prepared with a conventional cross-linking agent have poor deformability, strength, shear resistance, and further properties. Some researchers have prepared a new cross-linking agent using cyclodextrin (CD). In a polyrotaxane cross-linking agent, the cross-linking points can slide freely along the molecule chain. The special "slide ring" structure can provide better elongation, strength, and other properties to gels, which can effectively expand the application of the gel's materials. This paper summarizes the preparation methods and applications from different types of CD and compares the improvements of properties (swelling, viscoelastic properties, etc.). In addition, the current results of our group are presented, and some ideas are provided for the development of polyrotaxane cross-linking agents.

UV-Cleavable Polyrotaxane Cross-Linker for Modulating Mechanical Strength of Photocurable Resin Plastics

A UV-cleavable supramolecular cross-linker was designed to effectively control the mechanical strength of photocurable resin plastics. The resin monomer-soluble polyrotaxane (PRX) cross-linker was synthesized by introducing a hydrophobic n-butyl group and a cross-linkable methacrylate group in α-cyclodextrin threading to a polyethylene glycol containing UV-cleavable end groups. The UV-cleavable PRX cross-linker was completely dissolved in 2-hydroxyethytl methacrylate (HEMA) and camphorquinone, representative photocurable resin components. The dumbbell-like stiff resin plastic was prepared by irradiating the mixture with 450 nm blue light. The stiffened resin plastic maintained its ultimate tensile strength (UTS) under visible light irradiation. However, the UTS of the resin plastic was remarkably decreased to 40% of the original value once the plastic was exposed to 254 nm UV light. This indicates that the suggested UV-cleavable PRX cross-linker is effective in modulating the mechanical strength of photocurable resin plastics.